1. Field of the Invention
The present invention relates to data storage devices. More particularly, the present invention relates to rotating disk magnetic data storage devices.
2. Description of the Prior Art and Related Information
Rotating disk magnetic data storage devices, commonly referred to as disk drives, have undergone dramatic improvements in data storage capacity and data access times in recent years. At the same time, high performance, battery powered portable computers have become increasingly prevalent. Such portable computers require a high data storage capability in an environment limited in size and available power. These constraints imposed by such battery powered portable computers have provided a significant need for high performance disk drives having reduced power requirements.
Of the basic components of the disk drive, the actuator motor which drives the actuator which supports the read/write transducer heads, the spindle motor which rotationally drives the data storage disks, and the associated drive electronics, consume the most power. More specifically, the actuator motor, and associated motor driver and servo electronics, consume significant amounts of power both during track "seek" operations and "track following". Track seek operations, where the actuator moves the read/write heads to a desired track, require significant power since high acceleration/deceleration is desired to reach the destination track in minimum time. Track following also requires significant power since maintaining the read/write heads over a desired track requires continual adjustments by the actuator motor and servo electronics to offset drift and disturbing forces. The spindle motor in turn requires significant power to drive the data disks at a preferred speed during data input/output and track following operations. In particular, during start-up of the disk drive significant power is required by the spindle motor to overcome stiction to "fly" the read/write transducer heads.
Accordingly, for portable personal computers, which utilize batteries to provide electrical power, it should be appreciated that continuous operation of a high capacity disk drive may be very power intensive, significantly limiting useful computer time between battery replacement or recharging.
Further, all of the electrical components in the disk drive which are utilized during various drive operations generate heat. The generation of heat may require cooling means, such as fans, for the host computer requiring additional power. Also, high density integrated circuits are sensitive to temperature and the heat generated during power intensive disk drive operations may degrade the performance of the drive's integrated circuits. Thus, it is beneficial to minimize the power requirements of disk drives even for use with desktop computers or other computers not limited to battery power supplies.
An additional very important consideration for modern disk drives relates to maintaining high speed access to information stored on the disks. Thus, it is important that the power saving considerations be tempered with the need to have rapid access to data. Accordingly, any reduction in the power of operation of the disk drive should be accomplished in a manner whereby the impact on the speed of data access of the machine is minimized.
Accordingly, a need presently exists for a disk drive which avoids the above-noted problems.